Extrusion devices



Jan. 5, 1965 MULLER 3,164,253

EXTRUSION DEVICES Filed Aug. 2, 1962 lwnwme am: 7' M111 1.

JTTOANEY5 United States Patent Ofiice 3,164,253 Patented Jan. 5, 1955 EXTRUSIGN DEVICES Ernst Muller, Duisburg, Germany, assignor to Hydraulik G.m.l1.H., Duisburg, Germany Filed Aug. 2, 1962, Ser. No. 214,251 Claims priority, application Germany, Aug. 5, 1961,

3 Claims. (Cl. 207-) This invention relates in general to extrusion devices and in particular to a new and useful device for extruding molten metal billets from a billet container, including venting passage means defined therein in which a blocking or piston element is movable to close off the passage completely when venting is not taking place.

It is known to have extrusion presses with means for drawing oif or exhausting air which is trapped in the billet container. For this purpose usually one or several venting bores or channels are connected to open up into the interior bore of the container and these bores or channels are connected to a vacuum pump for exhausting the air. With known constructions of this character there is the disadvantage that the material being extruded may also enter these channels. With the operation of such de vices, therefore, it is necessary to clean the channels after each extrusion procedure and prior to the evacuation. This is usually done manually or by means of a known hydraulically driven plunger. In both instances, however, the cleaning of the evacuation channel is time consuming and moreover is not fully reliable. A particular disadvantage is, of course, the time lag resulting from the cleaning procedure. This is particularly troublesome for continuously operating extrusion procedures for producing an endless or uninterrupted extruded product, for example, a jacket or sheath for a cable.

In accordance with the present invention there is provided at least one venting channel or bore which connects into the billet container bore and in which is reciprocable a closure piston member. The invention advantageously includes a passage which is connected to the bore at widened diameter portion to evacuate the air from the billet container. In accordance with a feature of the invention the venting bore includes a small diameter portion Which connects directly into the billet container, and a closure piston is provided which includes a small diameter portion which reciprocates directly into the small diameter portion of the venting bore up to the interior wall of the billet container. The construction and operation is such that the mouths of the venting channels are closed except for a short period when evacuation of the billet containers takes place. The arrangement includes means, therefore, for timing the reciprocation of the closure piston with the movement of the extrusion plunger, and automatic means are included for insuring that the billet container vent channels are closed off when there is a likelihood of the billet material being forced thereinto. The cycle operates with the mouths of the venting channels being closed by the small diameter portion of the closing piston before and after the venting of the billet container. The closure piston may be any type of blocking member, such as a valve, piston slide or other element and is advantageously controlled by a hydraulic or other operating pressure source to move in timed relationship to the extrusion process.

The inventive arrangement advantageously includes a blocking member in the form of a closure piston which includes a frusto-conical intermediate portion which seats at the location of the change in diameter of the venting bores and which further includes an outer end which is made concave to correspond to the curvature of the interior of the billet container. Byinsuring that the inner end of the closure piston is made concave and adapted to the curvature of the wall of the bore of the billet container, it is insured that there will be no deposition of small nests or accumulation of metal in the spaces which are created by any deviation of the interior wall of the billet container cylinder.

A further feature of the invention is that the venting bores or channels include a small diameter portion which connects directly into the billet container interior and a larger diameter portion extending outwardly from the smaller diameter portion. The venting passage connects to the larger diameter portion on the side thereof, and communication between the venting passage and the small diameter portion of the venting bore is established when the piston is retracted within the large diameter portion of the venting bore.

A further feature of the invention is the control mechanism and system for actuating the power drive for the extrusion piston and the power drive for the blocking member or closure piston. The blocking element or closing piston is actuated in an opening direction by means of a switch element arranged in a fluid pressure system, which switching element is controlled in dependence on the position of the extrusion die piston. A vacuum pump is connected to the venting channel and the closure piston is retracted to permit communication of the venting channel with the small diameter portion of the venting passage. A vacuum meter is provided in the venting line which is also arranged to control the operation of the closure piston so that opening and closing movement thereof depends on both the movement of the extrusion piston as well as on the vacuum conditions which are obtained. This insures that the venting is entirely automatic and that the extrusion will be started immediately after venting takes place.

Accordingly, it is an object of the invention to provide an improved extrusion device.

A further object of the invention is to provide an extrusion device for molten metals which includes a billet container with at least one vent passage means connected directly into a container for the billet and comprising a vent channel in which is reciprocable a closure piston and an evacuation vent passage connected to the vent channel and to vacuum producing means, to the closure piston being movable to close off the vent channel at the location of the interior of the billet container and to prevent material from being lodged in the vent channel during all times except during actual venting.

A further object of the invention is to provide an extrusion press including a movable ram for extruding a billet through a die from a billet container with at least one venting passage means which comprises a vent channel including a small bore portion directly communicating with the interior of the billet container and a larger portion extending outwardly from the small portion, an evacuation passage connected to the larger portion in which there is applied a means for establishing a vacuum and including a closure piston member with a small diameter portion reciprocable in the small diameter portion of the venting channel to completely block off this chan nel up to the location of the interior bore of said billet container, and further including means for synchronizing the operation of said closure piston with the movement of the extrusion ram.

A further object of the invention is to provide an extrusion press which is simple in design, rugged in construction, and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawing and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

The only figure of the drawing is a transverse section of an extrusion press indicating schematically a control system for operating a vent passage blocking member constructed in accordance with the invention.

Referring to the drawing in particular, the invention embodied therein includes a billet container or receptacle 1 of a metal extrusion press. The billet container includes an interior liner 50 defining a bore 52 of the billet 7 container. A billet 2 is inserted in the billet container and it is shown abutting against or connecting with a residue 3 of the previous billet which was extruded through a die 54. A ram 7 is reciprocated under fluid pressure supplied in a ram press 56 and the ram 7 is moved against the billet 2 to cause the extrusion through the die 54.

p In accordance with the invention means are provided to exhaust or evacuate air which i trapped in the annular space surrounding the billet between the bore 54 of the billet container and the outer diameter 5 of the billet 2. For this purpose the annular space 4 is closed oil in the direction of the container mouth such as by a disc or a sealing head 6 formed at the end of the container 1.

Transverse to the bore of the billet container 1 there is arranged at least one venting means which includes a venting channel section comprising a small diameter bore or mouth 8 and a larger diameter bore or interior section 9. T he section 9 forms a guide cylinder for a blocking member which in the embodiment illustrated comprises a closure piston rod 10 which has a forward or upper end which is formed as a small diameter closure piston element or portion 11. The small diameter piston portion 11 is adapted to slide in the bore 8 and the outer tip thereof is adapted to be moved to a position at which it is flush with the interior surface of the bore 52 of the billet container. The tip is advantageously covered to conform to the configuration of the bore 52, so that there is no uneven surface within the bore after the closure piston ltl'i positioned in a closing position.

The widened section 9 of the venting means opens up to a venting line 12 which is connected to a vacuum meter and control 13 and a vacuum pump 14. The closure piston Ill is provided with a widened piston plug or disc portion 15 which is guided in a cylinder 16 under the control of fluid pressure admitted to alternate sides thereof through fluid pressure control lines 17 or 18. The control lines 17 and 18 are connected to a switching or reversing valve 19 which, in turn, is connected on the opposite side to either a high pressure line 26 or fluid evacuation line 21. Valve 19 is spring biased to one position and solenoid operated to the opposite position.

The operator of valve 19 is connected electrically in a circuit which includes a limit switch 22 which is actuated by movement of the ram 7. The switch 22 i connected via electrical control lines 23 and 24 to the operating element of the reversing valve 19 for changing the direction of flow in the control conduits 17 and 18. A further control is obtained by means of a switch 25 which is actuated in accordance with a preselected setting of the vacuum meter 13 arranged in the venting line 12. Switch 25 is included in series in conductor 24 so that the vacuum conditions control the positioning of the valve 19 along with the control by the position of the ram 7.

The vacuum pump 14 is driven by a motor 26 which is connected in an electrical circuit in such a manner that, upon retraction of the closure piston 10 from the mouth of the bore 8, the motor 26 is actuated. This actuation is produced by contact of a switching cam 28 formed at the end of the piston with a limit switch 27 connected in the electrical line 25 leading to a relay coil 30 of a relay switch. When the piston 10 moves upwardly, the contact Cam 28 moves Out of contact with the switch 27 and makes contact with a limit switch 31 so that the motor 26 is shut off and the line 12 is no longer subject to the vacuum produced by the pump 14. Conductor 33 connects the opposite end of the motor circuit into the same circuit which controls the switchings of valve 19.

After a new ingot has been inserted into the container 1 and the extrusion ram 7 has reached the position shown, the control switch 22 will be contacted by a member 22a to actuate the valve 19 to a position whereby the piston lid is retracted. The retraction of the piston l-tl causes the motor 25 to be energized due to closing of switch 2? by cam 28 with resultant energization of the relay 3%, and the vacuum pump 14 evacuates the line E2 to vent the billet container. After a predetermined vacuum is obtained, switch 25 is opened by means of the vacuum meter control 13, so that the valve 19 is again reversed to initiate the movement of the valve lltl back to its starting position. Pressurized fluid is then admitted to the line 13 to move the plug portion 15 in an opposite direction and the container bore is closed by the smaller diameter piston portion 11 entering the small bore 3.

When the closure device Ill-i is in its position closing the opening 8 into the bore 52 of the container, cam 23 actuates switch 31. Through the medium of conductors 32, 33 and 23, the actuation of the switch 31 provides a signal for the start of the extrusion process.

While a specific embodiment of the invention has been shown and described in detail .to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

l. A metal extrusion press comprising, in combination, a billet container having a billet receiving passage with an inner diameter greater than that of a billet to be extruded; a ram reciprocable axially into and out of said container passage; a seal on the end of said ram engageable with the inner surface of said passage to seal the entry end thereof when a billet in the container is engaged by said ram prior to extrusion; a relatively small diameter radial venting bore formed through the container Wall axially inwardly of the initial position of said seal and communicating with the billet passage; a relatively large diameter second bore communicating with the outer end of said venting bore and coaxial therewith; a venting passage communicating laterally with said second bore adjacent its junction with said venting bore; a plunger reciprocable axially of said bores and having a reduced diameter extension which, in one position of said plunger, enters and conformingly seals said venting bore, in the inner end of said reduced diameter extension being formed to conform to the inner surface of the billet passage; said plunger being movable to a second position establishing communication between said venting bore and said venting passage; double acting piston and cylinder means operable to move said plunger between its two said positions; and an electrically energized valve controlling connections of opposite sides of the piston of said piston and cylinder means to exhaust and to a source of fluid under pressure, said valve, when de-energized, being biased to a position controlling the connections of said piston and cylinder means to move said plunger to said one vent bore sealing position; an electric motor driven vacuum pump connected to said venting passage; mean operable, responsive to movement of said ram into the billet passage to engage a billet therein prior to extrusion, to energize said valve to reverse the connections to said piston and cylinder means to move said plunger to its retracted second position; and mean operable by said double acting piston and cylinder means, responsive to movement of said plunger to its retracted second position, to close an energizing circuit for the motor of said vacuum ump.

2. A metal extrusion press, as claimed in claim 1, in cluding a normally closed switch in the energizing circuit of said electrically energized valve; and means operable,

responsive to attainment of a predetermined vacuum in the billet passage of said container, to open said switch to de-energize said valve to again reverse the connections to said piston and cylinder means to move said plunger to said one venting bore sealing position. 5

3. A metal extrusion press, as claimed in claim 1, in-

cluding switch means operated by said piston and cylinder means when said plunger is in said one venting bore sealing position to close a circuit providing a signal for initiating extrusion of the billet in the container passage. 0

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Great Britain Apr. 11, 1956 

1. A METAL EXTRUSION PRESS COMPRISING, IN COMBINATION, A BILLET CONTAINER HAVING A BILLET RECEIVING PASSAGE WITH AN INNER DIAMETER GREATER THAN THAT OF A BILLET TO BE EXTRUDED; A RAM RECIPROCABLE AXIALLY INTO END OUT OF SAID CONTAINER PASSAGE; A SEAL ON THE END OF SAID RAM ENGAGEABLE WITH THE INNER SURFACE OF SAID PASSAGE TO SEAL THE ENTRY END THEREOF WHEN A BILLET IN THE CONTAINER IS ENGAGED BY SAID RAM PRIOR TO EXTRUSION; A RELATIVELY SMALL DIAMETER RADIAL VENTING BORE FORMED THROUGH THE CONTAINER WALL AXIALLY INWARDLY OF THE INITIAL POSITION OF SAID SEAL AND COMMUNICATING WITH THE BILLET PASSAGE; A RELATIVELY LARGE DIAMETER SECOND BORE COMMUNICATING WITH THE OUTER END OF SAID VENTING BORE AND COAXIAL THEREWITH; A VENTING PASSAGE COMMUNICATING LATERALLY WITH SAID SECOND BORE ADJACENT ITS JUNCTION WITH SAID VENTING BORE; A PLUNGER RECIPROCABLE AXIALLY OF SAID BORES AND HAVING A REDUCED DIAMETER EXTENSION WHICH, IN ONE POSITION OF SAID PLUNGER, ENTERS AND CONFORMINGLY SEALS SAID VENTING BORE, IN THE INNER END OF SAID REDUCED DIAMETER EXTENSION BEING FORMED TO CONFORM TO THE INNER SURFACE OF THE BILLET PASSAGE; SAID PLUNGER BEING MOVABLE TO A SECOND POSITION ESTABLISHING COMMUNICATION BETWEEN SAID VENTING BORE AND SAID VENTING PASSAGE; DOUBLE ACTING PISTON AND CYLINDER MEANS OPERABLE TO MOVE SAID PLUNGER BETWEEN ITS TWO SAID POSITIONS; AND AN ELECTRICALLY ENERGIZED VALVE CONTROLLING CONNECTIONS OF OPPOSITE SIDES OF THE PISTON OF SAID PISTON AND CYLINDER MEANS TO EXHAUST AND TO A SOURCE OF FLUID UNDER PRESSURE, SAID VALVE, WHEN DE-ENERGIZED, BEING BIASED TO A POSITION CONTROLLING THE CONNECTIONS OF SAID PISTON AND CYLINDER MEANS TO MOVE SAID PLUNGER TO SAID ONE VENT BORE SEALING POSITION; AN ELECTRIC MOTOR DRIVEN VACUUM PUMP CONNECTED TO SAID VENTING PASSAGE; MEANS OPERABLE RESPONSIVE TO MOVEMENT OF SAID RAM INTO THE BILLET PASSAGE TO ENGAGE A BILLET THEREIN PRIOR TO EXTRUSION, TO ENERGIZE SAID VALVE TO REVERSE THE CONNECTIONS TO SAID PISTON AND CYLINDER MEANS TO MOVE SAID PLUNGER TO ITS RETRACTED SECOND POSITION; AND MEANS OPERABLE BY SAID DOUBLE ACTING PISTON AND CYLINDER MEANS, RESPONSIVE TO MOVEMENT OF SAID PLUNGER TO ITS RETRACTED SECOND POSITION, TO CLOSE AN ENERGIZING CIRCUIT FOR THE MOTOR OF SAID VACUUM PUMP. 